1. Field of the Invention
The field of the present invention relates in general to a system for, and method of, multimedia processing in a computer system. More particularly, the field of the invention relates to a system and method for controlling priority and timing for processing different types (e.g. graphics, video, sound, etc.) of multimedia information, preferably in packets individually identifying (via headers, associated tags or the like) the different types of multimedia information.
2. Background
Personal computers and work stations have evolved rapidly since their introduction nearly twenty years ago. Dramatic advances in processor, display and audio technology have transformed the personal computer into a multimedia appliance, capable of combining color graphics, video, and stereo sound in a single software application.
However, most conventional systems require separate bus devices to support graphics, video, and sound. In fact, most sound devices are attached to the expansion bus, while graphics and video devices have migrated to the local bus to take advantage of higher data transfer rates.
Unfortunately, this piecemeal approach to providing multimedia capabilities has led to the development of separate graphics, video, and audio subsystems having independent controllers with incompatible data types. This may lead to wasted memory space and memory bandwidth, duplicated bus interface logic, and wasted CPU cycles to manage independent subsystems.
A significant problem with conventional approaches has been that different types of multimedia information have been stored in different memories. For example, sound information has been stored in one (1) memory for subsequent processing and graphics and video information has been stored in another memory. This has prevented each memory from being used efficiently. It has also caused the multimedia system to be relatively expensive and to occupy a relatively large amount of space.
A further significant problem exists in conventional systems. This results from the fact that information for the different types of media has not been packetized. This prevents efficient identification and processing of information relating to the different types of multimedia information. It also inhibits the information relating to the different types of media from being mixed into a single stream.
An additional significant disadvantage in conventional systems has been that each different type of media has been provided with its own independent interrupt line to control the processing of that media. This has limited the number of interrupt lines available for other uses. It has also resulted in the use of additional pins or connectors in the system and additional complexity in the configuration and installation of the system.
What is needed is an apparatus and method for combining graphics, video, and audio in a single bus device, using a single bus interface. Preferably, such a system would allow the sharing of a single buffer and other components for use in various multimedia applications, including audio, graphics, video input, and video output. Preferably, such a system would also allow the format and processing of multimedia information to be flexibly controlled by software.